Lithium-induced respecification of pattern in Xenopus laevis embryos

Abstract

Much interest in vertebrate embryology is now focused on early pattern formation in the frog, Xenopus laevis. In this species, the body plan is specified by a stable positional system set up by a cytoplasmic rotation in the zygote that occurs before first cleavage. Perturbation of this initial cellular event by a variety of means causes permanent distortions of the positional system. Until now it has not been possible to alter the positional system after it has been specified. However, we report here that lithium, when applied after specification of the body plan, can respecify the positional system of the Xenopus embryo such that dorsal, axial structures develop from cells that otherwise contribute to ventral structures. Lithium is usually considered to have negative effects on early embryo development, but our results show that lithium can act in a positive manner to produce structures which represent the uppermost values of the positional system. This discovery introduces a convenient means to study cellular and molecular mechanisms of early vertebrate pattern expression.

Identification and regulation of glycogen synthase kinase-3 during bovine embryo development

“…Lithium also interferes with another second messenger system, the inositol pathway causing selective reductions of PKC (Manji & Lenox 1999), which has been shown to phosphorylate and inactivate GSK3 mediating acentromeric spindle stabilization in mouse oocytes (Baluch & Capco 2008). This reduction in cAMP concentration or PKC by lithium in bovine embryos would lead to a decrease in the phosphorylation of GSK3, as observed here, and may explain the detrimental effect on embryo development as previously shown in mouse, rabbit, and Xenopus embryos (Kao et al 1986, Fahy & Kane 1994, Rogers & Varmuza 1996. In the present study, because both inhibitors reduced b-catenin phosphorylation, the detrimental effect of lithium on bovine embryo is mainly mediated through other signaling pathways leading finally to a decrease in the phosphorylation of GSK3 and a reduction in embryo development.…”

“…In zebrafish, lithium exposure produces excessive shield formation and extreme hyper-dorsal development (Stachel et al 1993). In Xenopus, it causes an expansion of dorsal mesoderm, leading to duplication of the dorsal axis or, in extreme cases, entirely dorsalized embryos (Kao et al 1986). A short treatment with lithium chloride (LiCl) at the two-or eight-cell stage causes mouse embryos to develop axial defects similar to those observed in some mutations that adversely affect gastrulation (Rogers & Varmuza 1996).…”

The Initiation Factor eIF4A Is Involved in the Response to Lithium Stress in Saccharomyces cerevisiae

“…In fact, the first studies on lithium action were on phenotypic effects on development. LiCl induces vegetalization in sea urchin embryos (26) and inhibits the formation of the dorsal-ventral axis in Xenopus laevis embryos (27) and the cell fate determination in the slime mold Dictyostelium discoideum. Wolcott (28) demonstrated that vegetalization was induced only to impaired protein synthesis and not to mRNA degradation.…”

Isoquercitrin Suppresses Colon Cancer Cell Growth in Vitro by Targeting the Wnt/β-Catenin Signaling Pathway

“…Then the flavonoids or DMSO were removed and the embryos were cultured until stage 32. Axis phenotypes were scored by the dorsal-anterior index (DAI) (21).…”